Home / Questions / 499070
Accepted
Emy
Asked: 2022-04-24 12:49:20 +0800 CST 2022-04-24 12:49:20 +0800 CST

Filter and remove property from an array

  • 772

I have an array formed as follows:

descriptionAndItem = [
    {
      description: 'Transaction A',
      items: [
        { status: 1, description: 'Item A', code: 4 },
        { status: 1, description: 'Item B', code: 3 },
      ],
    },
    {
      description: 'Transaction B',
      items: [{ status: 0, description: 'Item C', code: 8 }],
    },
    {
      description: 'Transaction C',
      items: [
        { status: 1, description: 'Item D', code: 4 },
        { status: 0, description: 'Item E', code: 8 },
      ],
    },
  ];

From that information I must filter only those that have the status of the item equal to one, for this I use the function filterand findin the following way:

let filterData = this.descriptionAndItem.filter((x: any) =>
    x.items.find((y: any) => y.status === 1)
);

But when there is more than one item and only one of them has the status equal to one, the filter also shows the item that has the status equal to zero. How could I do the filtering so that it does not show that item or eliminates it.

item

Demo: Stackblitz

javascript

2 Answers

  1. Best Answer

    You could iterate through your parent array using reduce , and within it use filterto get the elements that meet the conditions.

    const descriptionAndItem = [{
    description: 'Transaction A',
    items: [{
        status: 1,
        description: 'Item A',
        code: 4
      },
      {
        status: 1,
        description: 'Item B',
        code: 3
      },
    ],
  },
  {
    description: 'Transaction B',
    items: [{
      status: 0,
      description: 'Item C',
      code: 8
    }],
  },
  {
    description: 'Transaction C',
    items: [{
        status: 1,
        description: 'Item D',
        code: 4
      },
      {
        status: 0,
        description: 'Item E',
        code: 8
      },
    ],
  },
];

(() => {
  const result = descriptionAndItem.reduce((prev, curr) => {
    const aux = curr.items.filter(i => i.status === 1)
    
    if (aux.length > 0) {
      const add = { ...curr, items: aux }
      prev.push(add)
    }
    
    return prev
  }, [])

  console.log(result)
})()

    The key is inside the if, in which we create a constant that will have the element that is going through, and to that element we attach only the corresponding items .

    You tell us how it goes.

    • 0

  2. The best way in my opinion is using .reduce, but following the logic you used, you should use another .filterinside .filter(instead of .find). Because there are two things you want to filter, "transactions" and "items". What happens is that .filterit does not alter each element, it is only trueor false, it is complete or it is not. But this does not prevent us from manually altering it before telling it that this or that element will be "allowed" ( true). Then you could do:

    const descriptionAndItem = [{"description":"Transaction A","items":[{"status":1,"description":"Item A","code":4},{"status":1,"description":"Item B","code":3}]},{"description":"Transaction B","items":[{"status":0,"description":"Item C","code":8}]},{"description":"Transaction C","items":[{"status":1,"description":"Item D","code":4},{"status":0,"description":"Item E","code":8}]}];

let filterData = descriptionAndItem.filter((x, i, o) =>
  (o[i].items = x.items.filter(y => y.status === 1)) && x.items.length
);

console.log(filterData);

    Where the third parameter of the first .filteris the original array, it is the same as if we used descriptionAndItem.

    In this way, in each iteration of the first .filterwe alter the original array (represented with o) before deciding whether it will be there or not, said alteration is another .filter. After the alteration, if it turns out to itemshave zero elements, the parent of will not be included itemsin the final array.

    • 0